This invention relates to circuit protective arrangements and more particularly relates to a novel high capacity circuit breaker having coordinated ground fault interruption means.
It is known to series connect a circuit breaker and current limiting fuse device to achieve reliable current interruption when connected to a source having an available current in excess of the rated current interruption rating of the circuit breaker, even when the source voltage is above the rated voltage of both the circuit breaker and current limiting fuse devices, as in U.S. Pat. No. 3,599,135 issued Aug. 10, 1971, to the assignee of the present invention. There is presently a great interest in providing ground fault protection for operation with circuit protective arrangements useful in light and medium industrial applications at relatively low costs.
In the prior art coordinated operation of the circuit breaker and current limiting fuse devices, where a current interrupting process is initiated by closely-cooperating thermal, electromagnetic, fuse protection and fuse removal means, it is necessary to have a unit with high component density in the area of the circuit breaker separable-contact trip mechanism. This high packaging density has hitherto not allowed the incorporation of ground fault protection means cooperating with the trip mechanism to provide desired additional protection in the event of a ground fault condition occurring in a power utilization device or on the pair of power lines coupling such device to the circuit breaker.